If certain abilities/talents/skills/classes trivialize the game, the nerfs are more than acceptable.
It's funny how you claim that PoE is not a "freaking MMO" and then proceed to complain about "builds."
Well yeah, it's an rpg, so if a spell is too powerful, it's up to you to decide if YOU want to use it, or not. Not somedy else.
And yes, again, it's an rpg, you build the character you want, the way you want it. Builds or templates or whatever arn't born fromm MMOs dude. You're playing it alone, you don't care about what other think, it's you and you alone.
Why nerf some ? Because it's too powerfull ? Don't use this spell/talent/ability then, you're not competiting against anyone here. Or maybe because you don't need to use other spells because there's this one who work better ? Up to you, once again.
You want to use those ? then use them, but don't make it on others because you think it's acceptable or needed, once more, this is a solo game; builds are made through various means and aiming to various goals, each personal, and not because of the sake of "balance" or "having the best you can get", like Mmos do.
It's their game and their IP. They decide how powerful they want skills, abilities and spells to be so it fits their vision of how they want their game to be. If you don't like it, look for future modding opportunities that will let you cast spells that one-shot the entire screen.